Characterization of an electrochemical hydrogen pump with internal humidifier and dead-end anode channel

Electrochemical hydrogen pump (EHP) with an internal humidifier is reported. The internal humidifier contains liquid water stored in a vessel built in the cathode end plate, and the water directly wets a polymer electrolyte membrane (PEM). By using the internal humidifier, conductivity of the PEM is higher than that using a conventional vapor humidifier. A modeling of water transport is built to discuss the water balance in the membrane. Electrochemical impedance spectroscopy (EIS) is employed for analyzing the resistance components included in the EHP. In particular, the effects of compression ratio on resistance components are investigated.